McArthur Group Ltd

Galvanising

The Hot Dip Galvanizing process has been around for one hundred and fifty years. The process is a means of protecting steel against corrosion. Protection is by means of coating the steel work with zinc. The process is carried out by cleaning the material in hydrochloric acid to ensure a chemically clean surface. Steel work is then fully immersed into a tank containing liquid zinc held and controlled at 450 deg. C. The zinc reacts with the steel surface which forms a series of zinc iron alloy layers which are metallurgicaly bonded to the steel substrate. This gives a coating which even when damaged in small areas, will provide an impenetrable layer to the steel substrate.

P R O D U C T I O N P R O C E S S

In Comparison to other corrosion protection systems, Hot Dip Galvanizing provides protection to both side surfaces of hollow sections. For this to be successfully carried out, fabrications need to be vented allowing the zinc to enter at the lowest point and for the free passage of air to escape at the highest point (see above). This is a most important consideration at the design stage of a fabrication, as inadequate venting can lead to potential production problems.